Currently, the option to switch the customer's label is unavailable in QuickBooks Desktop. Though, I have a workaround that you may want to consider.
You can toggle your QuickBooks Desktop edition to Enterprise Solution Nonprofit. You can do that by clicking the File menu and selecting Toggle to Another Edition. Then, choose Enterprise Solution Nonprofit.
Continue with the on-screen instructions to successfully use the Donor label.
You can also send feedback to our developers so they may add this option in the next update. Let me guide you on how:
Tap on Send Feedback Online, then Product Suggestion.
Choose a feedback type and product area on the QuickBooks Feedback window. Enter your suggestion or feedback, name, and email address (optional), then click on the Send Feedback button.